Cell c sent me a paid up letter with one of their clients details

I really tired of this issue now with receiving my paid up letters, yes someone did get back to me but they sent me an email with a paid up letter that belonged to someone else and when I call I still go through the same things like I don't understand what you guys want me to do like it's old now guys I have had enough of this issue, my life is basically on hold for a piece of paper and every time I have to come here to complain to get help like this is totally unacceptable